Author Topic: Help me build a 520 inch stroker for the street ? (Read 4160 times)

Todd Smith · « **on:** May 07, 2011 - 11:31:20 AM »

I came across this motor (lower end only) several years ago. Was and excellent deal at the time. Only had a few passes on it. You can still see all the cross hatching in the cylinders and she spins nice and smooth. I haven't taken it apart yet, but polish the crank, new rings and bearings plus a balance and I think she'll be good to go. Has a 4.350 bore, 4.373 stroke and a zero deck.

I also have a set of NOS stage IV mopar iron heads, still in the factory boxes. I'll Hog the heads out so she can breathe some. Problem hear is, if I drop the 80cc heads on, with a standard head gasket, I'm at 13.75:1 compression. Hardly steetable.

I found these guys http://www.4secondsflat.com/cometic.html they make a .10 head gasket that should drop me to 11.2:1 which is manageable. Anybody ever use these guys stuff??

For a cam, I figured I'd go with a roller in the high 500's and a gear drive - just because I have the gear drive.

I haven’t decided what to do about feeding it gas. I'm at 6000 feet elevation and for a carbureted
motor that's tough. Maybe a FAST EFI for drivability?

It's a 4 speed car. I thought 355's or 391's with 295/50/15's and maybe a gearvender unit.

Been a long time since I've planed a motor and drive train out. Am I on the right track or have I lost my marbles.
Here is where I got my compression #s http://www.mymopar.com/compression.htm

Thanks

BB73Challenger · « **Reply #1 on:** May 07, 2011 - 06:21:46 PM »

The Cometic head gaskets are considered some of the best, that's what I used on my stroker.

I don't have a lot of confidence in 11+ to 1 comp in a high elevation iron headed engine... I ended up using Eddy's aluminum 88 cc heads to get around my high comp issue. *This Might NOT be a problem... I just read high altitude should HELP*

Now depending on your cam choice, that will play into as well. I think that may be the next thing to start throwing numbers at.

I'm also running 3.55 to 1 rear with NO OD. And they are great on the streets, but would like to go with some kind of OD for extended freeway use.
Plus with 500+ cubes I wouldn't even bother with a street car and a higher rear, you will be spinning out of the whole as is.

I'm sure we will get more opinions...

PS... on the gear drive..
I ALMOST ran one on the stroker I have going, but opted no.
Yes, it's all a matter of taste on the sound, and yes I may be in the minority that thinks they sound cool, but after doing a bunch of reading, they had a lot of negative feedback. I'm sure this too we will get some opinions on.
I stuck with the double roller chain.

Strawdawg · « **Reply #2 on:** May 07, 2011 - 08:29:50 PM »

for the street and efi, a tamer cam might be nice...unless you want to go to a fullblown efi like the FAST XFI, BigStuff3, etc.

Chryco Psycho · « **Reply #3 on:** May 07, 2011 - 10:54:07 PM »

Cometics are awsome gaskets , they are available directly from Cometic
you need to use a closed chamber head to kill detonation , I can't remember if the Stage 4 head was closed chamber , with the long duraation cam & high altitude you may get away with Pump Gas

Road_Runner · « **Reply #4 on:** May 08, 2011 - 12:22:33 AM »

Sounds like a stout engine combo, for the trans you ought to give a look at Passon Performance's new overdrive Mopar 5 speed. Plenty strong enough for your engine and will bolt right in with no mods. That's what I have planned for a similar build for the Roadrunner. Depending on what rear gear I go with on the Barracuda I would definitely consider a Gear Vendors unit on the back of the 904.

Later, Jim

BB73Challenger · « **Reply #5 on:** May 08, 2011 - 08:34:18 PM »

Quote from: -Sledgehammer- on May 08, 2011 - 05:12:42 PM

Im a fan of geardrives

Now there are 2 "styles" of gear drive... is 1 better or a must over the other.

I've seen 3 gears and 4 gears (most common & seem the cheapest)

brads70 · « **Reply #6 on:** May 08, 2011 - 08:53:22 PM »

Just learning......

Chryco Psycho · « **Reply #7 on:** May 09, 2011 - 01:43:28 AM »

Pete Jackson has a quiet gear drive , still has s ound to it but minor compared to the noisy ones !!

brads70 · « **Reply #8 on:** May 09, 2011 - 07:35:29 AM »

The Challenger video still makes me smile. " Don't go fast OK"

Todd Smith · « **Reply #9 on:** May 09, 2011 - 12:27:06 PM »

Guys! You all jumped right in this thread, Thank you!
I'm glad the Cometics gaskets are a good piece. I didn't want to try shaving tops off pistons or junk like that

So far gear drive gets the big vote (Good ---- cause I have it)

Chryo, I'll have to look a the heads, I can't remember if they are open or closed either. They had never been out of the box till I took the pics for this post. I'll look today when get home from work.
I did read somewhere they take an offset rocker

Jim - I've bought stuff stuff from Passions before. New 5 speed is VERY cool. They don't have the pricing for it up on the web yet. There's a call to make.

Sledgehammer - Thanks for the cam suggestion. Don't go so fast video is great.

You guys have me all reved up now --- THANK YOU--- I needed that. I live out in the country and don't or didn't have anyone to share this stuff with. Having people that understand this addiction and have so much knowledge, makes it even more fun.

I'll tear down the short block and pull together the parts I have so we know just what we have to work with.

Todd

jimynick · « **Reply #10 on:** May 10, 2011 - 10:59:48 PM »

Todd, I'm sure not Dick Landy, but everything I've read says to set your piston/head clearances to .030-.040 to improve mixture homogeniety, quench, burn rate and detonation resistance and .100 was always mentioned as a # to avoid because of the loss of quench. Cometic make excellent gaskets in any thickness you should need. The MLS (multiple layer steel) are the way to go. I'd put those sweet MaxWedge heads back in their boxes and buy the Edelbrock or Indy heads with enough of a chamber and flow rate to make the CR/power that you need. There was a mention about the dynamic CR and that's the number you should keep your eye on. As mentioned, the cam will make a big difference based on duration and LDA (lobe displacement angle) and some time on Comps Cam Help line once you get a list together may prove enlightening. Should be a real killer when you get it together!

Todd Smith · « **Reply #11 on:** May 11, 2011 - 01:44:09 PM »

Quote from: jimynick on May 10, 2011 - 10:59:48 PM

Todd, I'm sure not Dick Landy, but everything I've read says to set your piston/head clearances to .030-.040 to improve mixture homogeniety, quench, burn rate and detonation resistance and .100 was always mentioned as a # to avoid because of the loss of quench. Cometic make excellent gaskets in any thickness you should need. The MLS (multiple layer steel) are the way to go. I'd put those sweet MaxWedge heads back in their boxes and buy the Edelbrock or Indy heads with enough of a chamber and flow rate to make the CR/power that you need. There was a mention about the dynamic CR and that's the number you should keep your eye on. As mentioned, the cam will make a big difference based on duration and LDA (lobe displacement angle) and some time on Comps Cam Help line once you get a list together may prove enlightening. Should be a real killer when you get it together!

Jimmynick
As much as I'd like to go with what I have, I believe you�re correct. The heads are "open chamber" and that's gona be a problem with detonation at that compression. I tore the short block down and I'm having a little piston problem

Here is a pic of # 2

I haven't figured out if it was a defect in the piston or something didn't quite get the clearance it needed. A couple thousands could have been the culprit when the motor came to temp.

Anybody know where to find 1 Venolia piston? The other 7 are beautiful and the crank and bearings that came out were perfect.

Did someone buy Venolia out? Gona screw me for 4 - 500 bucks if I can't find it.

But yes, plan A just took a dump! Upside is, Plan B, whatever that is + the elusive $ will get me to wherever we need to go to find ROLLING THUNDER...Please keep the wisdom coming.

I REALLY appreciate you all

HP2 · « **Reply #12 on:** May 11, 2011 - 02:28:56 PM »

Quote from: -Sledgehammer- on May 08, 2011 - 05:12:42 PM

Id say by looking at your pistons they are maybe -6cc valve reliefs and with a 4.450/.060 (.060 quench also cause zero deck) cometic Im coming up with 11.51 to 1 also assuming a 6.760 rod and the comp Xr286R street roller puts your dynamic compression @ 7.70 to 1 and about 150psi cylinder pressure which would be good for pump fuel at your altitude! the comp XR286 has an intake valve closing ABDC of 69 which aids in bleeding off some cylinder pressures.

That may work, but much more than that is iffy. Where he is at 91 octane is the best available and it is is cut by 10% ethanol. My 440 at 170 psi does occasionally have detonation problems with that same gas and an agressive spark curve.

Todd Smith · « **Reply #13 on:** May 11, 2011 - 05:08:23 PM »

Quote from: -Sledgehammer- on May 11, 2011 - 03:21:38 PM

good point HP2. My mindset is always just filling up with pump 93! he may be alright though! just gotta find out I guess! However looking at that piston that just looks like maybe a brittle break or something and I'd dont think i could just trust the rest of the pistons in that set! me personally, I would buy a whole new set and be done with it and get everything where you want to be! I run diamond pistons and its nice they will send you just 1 piston if needed!

Sledgehammer
I have looked at the other 7 pistons. The metal supporting the ring on the #2 is noticeably thinner. NICE quality controll

I agree that a complete new set would be "Best world"
But I'd be OK with a single replacement--------------------- I think $:-\$
Problem is where to get one.
If I have to go with new heads AND new pistons, it's gona be a set back. That being said, doing it right the first time, is key.

Keep it coming guys................. I'm learning a lot. I'd be lost in this stroker without Ya!!!!

I'm off to work

jimynick · « **Reply #14 on:** May 11, 2011 - 10:55:21 PM »

Todd, is it my eyes or is the oil ring a bit blue on that #2 slug. Blue means heat- is the bore scuffed at all? You know, the purists will scream, but if you could source a piston of the same configuration and near weight, you could balance it to the same weight as the Venolia slug and stick'er in, manufacturer be damned! The engine can't read the name on the box. Check cylinder taper while you've got the pistons out. Good thing you found this $hite out now, rather than at 6000rpm, later. I'd roll the rings off a few and check end gap while I was at it, as well, mind the orientation of the rings when you remove them. Ah, what fun, eh?

Author Topic: Help me build a 520 inch stroker for the street ? (Read 4160 times)

Todd Smith

Help me build a 520 inch stroker for the street ?

BB73Challenger

Re: Help me build a 520 inch stroker for the street ?

Strawdawg

Re: Help me build a 520 inch stroker for the street ?

Chryco Psycho

Re: Help me build a 520 inch stroker for the street ?

Road_Runner

Re: Help me build a 520 inch stroker for the street ?

BB73Challenger

Re: Help me build a 520 inch stroker for the street ?

brads70

Re: Help me build a 520 inch stroker for the street ?

Chryco Psycho

Re: Help me build a 520 inch stroker for the street ?

brads70

Re: Help me build a 520 inch stroker for the street ?

Todd Smith

Re: Help me build a 520 inch stroker for the street ?

jimynick

Re: Help me build a 520 inch stroker for the street ?

Todd Smith

Re: Help me build a 520 inch stroker for the street ?

HP2

Re: Help me build a 520 inch stroker for the street ?

Todd Smith

Re: Help me build a 520 inch stroker for the street ?

jimynick

Re: Help me build a 520 inch stroker for the street ?